Anchoring system

ABSTRACT

An anchoring device having a length of reinforcing material, a shell section attached to the reinforcing material, wherein the shell section has a hollow inner core, and a wedge located at least partially in the inner core of said shell section. In one embodiment, the wedge section is integral with the reinforcing material. In a preferred embodiment, the shell section has four segments and the wedge and the shell section have circumferential barbs on an outer portion thereof to provide greater retention properties for the anchoring system. One embodiment of the present invention also includes a method of attaching a reinforcing structure having a first end, a second end, and a longitudinal axis to an existing substrate, the method including the steps of drilling an aperture in the substrate, inserting the first end of the reinforcing structure in the aperture, the first end containing a shell portion attached thereto, the shell portion having a hollow inner core, the shell portion further containing a wedge partially inserted in the hollow inner core. The method further includes, in one embodiment of the invention, hammering the second end of the reinforcing structure in a direction parallel to the longitudinal axis and toward the aperture, wherein the hammering causes the wedge to be driven into the hollow inner core, thereby causing the end of the shell portion to flare outward and against the walls of the aperture.

FIELD OF INVENTION

This invention relates generally to reinforcement bar (“rebar”) and other types of reinforcing structures used in concrete or other masonry structures, and in particular structures and methods used to attached such reinforcing structures to existing concrete and masonry.

BACKGROUND OF INVENTION

Rebar, thread rods and other types of reinforcing structures are well known in the concrete/masonry fields, which are used to reinforce concrete and masonry. For instance, with respect to concrete, it is typical to lay a matrix of rebar in an area that will be filled with concrete. When the concrete is poured into the matrix of rebar, the rebar and cured concrete form a structure that performs well in the presence of both tensile and compressive loads. However, it is sometimes desired to attach rebar to an existing cured concrete structure for the purposes of allowing poured concrete in the next constructional stage of a structural design to form an integral unit with the pre-existing, cured concrete. In such a scenario, a portion of a length of rebar is attached to the cured concrete and the rest of the length of rebar is left exposed so that it can be engulfed by uncured concrete in the next constructional stage. Alternatively, at times, it is necessary to attach rebar to an existing, cured, concrete structure for purposes of repair.

At present, a widely used method of attaching rebar (and other reinforcing structures, such as thread rod) to existing cured concrete or masonry structures utilizes an epoxy anchoring system. Under such a method, a hole of the appropriate size and depth for the rebar (or threaded rod) is drilled into the cured concrete and/or masonry structure. The hole is then cleaned out and a predetermined volume of mixed epoxy is placed in the hole. Next, the rebar is inserted into the hole and the epoxy is allowed to cure before the new concrete is poured.

While such epoxy anchoring methods can produce the joint/bond strengths required for design requirements, these methods have several shortcomings. First, they are time consuming because of the time needed to mix and dispense the epoxy. Moreover, even if the epoxy is pre-mixed, such pre-mixed epoxy has a limited shelf life and must be stored under the proper conditions or else the epoxy will be spoiled. Second, the metering and dispensing of epoxy can be problematic. Indeed, in floor applications, overflow and waste of the epoxy can occur if too much epoxy is placed into the hole. Conversely, if too little epoxy is used, the rebar will not attain the desired structural bond to the existing concrete. Moreover, in wall and overhead applications, special dispensing and retention products are required in order to try and keep the proper volume of epoxy in the hole while the rebar is inserted and while the epoxy is curing. Oftentimes, epoxy in these wall and overhead applications will run out of the hole, thus causing waste and clean-up problems for the construction site and the installer. Third, the quality and cure times of an epoxy depends on many variables, including ambient temperature, ambient humidity, substrate temperature and substrate moisture content. Due to these variables, an epoxy must be customized for each particular job so that it is usable under the prevailing conditions. Moreover, because of the cure times involved with epoxy, construction delays can ensue, giving rise to increased construction costs. Lastly, because epoxies are made of materials that may be hazardous, special safety equipment and procedures must be employed when using an epoxy.

Accordingly, there is a need for an alternative rebar, thread rod (or other reinforcing structure) anchoring system that addresses the above-identified issues

These and other needs will become more apparent upon a review of the specification, drawings and claims, set forth below.

SUMMARY OF THE INVENTION

One embodiment of the invention comprises an anchoring device having a length of reinforcing material, a shell section attached to the reinforcing material, wherein the shell section has a hollow inner core, and a wedge located at least partially in the inner core of said shell section. In one embodiment, the wedge section is integral with the reinforcing material. In a preferred embodiment, the shell section has four segments and the wedge and the shell section have circumferential barbs on an outer portion thereof to provide greater retention properties for the anchoring system. One embodiment of the present invention also includes a method of attaching a reinforcing structure having a first end, a second end, and a longitudinal axis to an existing substrate, the method including the steps of drilling an aperture in the substrate, inserting the first end of the reinforcing structure in the aperture, the first end containing a shell portion attached thereto, the shell portion having a hollow inner core, the shell portion further containing a wedge partially inserted in the hollow inner core. The method further includes, in one embodiment of the invention, hammering the second end of the reinforcing structure in a direction parallel to the longitudinal axis and toward the aperture, wherein the hammering causes the wedge to be driven into the hollow inner core, thereby causing the end of the shell portion to flare outward and against the walls of the aperture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of an anchoring system of one embodiment of the present invention.

FIG. 2 is a top plan view thereof;

FIG. 3 is a cross-sectional view showing an anchoring system of one embodiment of the present invention installed in a substrate;

FIG. 4 is a cross-sectional view showing an anchoring system of one embodiment of the present invention installed in a substrate;

FIG. 5 is a partial cross-sectional view showing a barbed wedge inside of a shell portion of one embodiment of the present invention;

FIG. 6 is a side elevational view of a wedge in one embodiment of the present invention;

FIG. 7 is a cross-sectional view of a portion of a shell section of one embodiment of the present invention;

FIG. 8 is a partial cross sectional view of a portion of a shell section of one embodiment of the present invention joined to a piece of reinforcing material; and

FIG. 9 is another embodiment of the anchoring system of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While the present invention is capable of embodiment in various forms, there is shown in the drawings and will be hereinafter described a presently preferred embodiment with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated.

With reference to FIG. 1, one embodiment of the anchoring system 10 of the present invention includes a length of rebar 12, a shell section 14 and a wedge 16. It will be appreciated that although a length of rebar 12 is shown and described in one embodiment of the present invention, any other type of reinforcing structure used with concrete or masonry structures, such as, for instance, threaded rod, can be used in the practice of the present invention.

In one embodiment of the invention, the shell section 14 has a hollow inner core and is segmented into four grippers 18 at one end thereof. It will be appreciated, however that more or less gripper segments can be used in the practice of the present invention. For instance it is possible that just two gripper segments can be used in the practice of the present invention. Moreover, it is possible that, using proper materials that would allow for proper installation, the shell section need not be segmented at all. As shown in FIGS. 3 and 4, these grippers 18 are driven outward when wedge 16 is driven toward the rebar 12 during an installation process, which is described in more detail below.

In a preferred embodiment, the sizes of dimensions A, B, C and D, shown in FIG. 1, for rebar size numbers 3, 4 and 5 are shown below in Table I: TABLE I Dimension Dimension Dimension Dimension “A” “B” “C” “D” Rebar Size (mm) (mm) (mm) (mm) #3 450 40 18 14 #4 600 50 22.9 17.5 #5 750 60 30 21.7

In one embodiment of the present invention, the wedge 16 is frusto-conical in shape and may contain circumferential locking barbs 20, which act to lock the wedge 16 in place after being driven toward rebar 12. Preferably, there are four such circumferential barbs 20 in a 10 degree by 15 degree profile, as shown in FIG. 6. In one embodiment, the barbs 20 may engage detents 22 on shell section 14 for increased locking forces between the wedge 16 and the shell section 14. Moreover, for better locking forces between the grippers 18 and the concrete or masonry (shown in FIGS. 3 and 4 as reference numeral 24), the grippers 18 may also contain circumferential barbs 26 on the outer diameter thereof. In a preferred embodiment, there are four such barbs 26, which have a ledge portion 28 that is approximately 0.010 inches wide, is at an approximately 5 degree angle, as shown in FIG. 5, and has an angled portion 30 that is at an 100 degree angle to the horizontal. Detents 22 are also preferably angled at 10 degrees from horizontal, as shown in FIG. 7. Those with skill in the art will recognize that other angles and dimensions than those specifically discussed herein for the barb structures on the shell section 14 and the wedge 16 are within the scope of the present invention. Moreover, although four circumferential barbs are used on the wedge 16 and the grippers 18 in a preferred embodiment, it will be appreciated that more or less barbs may be used in the practice of the present invention.

While some embodiments of the present invention use circumferential barbs on the wedge 16 and shell section 14, it should be noted that the present invention is not limited to structures that use such barbs. Indeed, as shown in FIGS. 3 and 4, the wedge 16 and the shell section 14 in these figures do not include barbs. It is envisioned that such structures not containing the barbs can be used in less-stringent load requirement applications. Moreover, as shown in FIGS. 3 and 4, the wedge 16 may be tapered throughout, as shown in FIG. 4 or may have tapered and non tapered section, 16 a and 16 b, respectively. It is believed that a wedge having a continuous taper will provide enhanced locking forces.

Preferably, the shell section 14 and the wedge 16 are made of a high quality, low carbon steel, such as SAE/AISI 1010 that is heat treated to allow micro compression during installation and at the same time retain its mechanical properties. Those with skill in the art will appreciate, however, that other types of steels or other materials can be used in the practice of the present invention. In a preferred embodiment, the steel of shell section 14 and wedge 16 is heat treated by carbonnitriding at 1450-1650 degrees Fahrenheit using a cooling medium of oil and tempering at 250-400 degrees Fahrenheit The shell section 14 and the wedge 16 are also preferably zinc plated using a dichromate wash, which helps the shell section 14 and the wedge 16 resist oxidation due to the corrosive nature of concrete.

In order to attach the shell section 14 to the rebar 12, it is preferred to utilize a macro-controlled swaging process, which results in a reduced diameter portion 34 on the swaged section of shell section 14, as shown in FIG. 1 As is known in the art, such a swaging operation uses a hydraulic press and a set of specially designed closed dies, which are controlled by a computer to ensure consistent and uniform shell material formation around the outer diameter of the rebar 12. As is shown in FIG. 8, the swaging operation presses the shell material into the recesses of the rebar, thus “locking” the two pieces together. The resultant connection between the rebar and the shell section using such a swaging operation has been found to be stronger than the bond requirements between rebar and concrete. Alternatively, the shell section 14 can be attached to the rebar 12 via welding, epoxy or any other attachment scheme that will provide sufficient retention forces to prevent the rebar 12 from separating from the shell section 14 under load conditions. Also, in the case of a threaded rod, the shell section 14 can contain internal threads that are designed to mate with the threads on the threaded rod, and the two pieces are connected by threading the threaded rod into the shell section and tightening the same.

A method of installing the anchoring system of one embodiment of the present invention will now be described. First, a hole is drilled in the concrete or masonry structure to the particular diameter and depth of the specific rebar and/or threaded rod to be used. After all debris is removed from the hole, the anchoring system 10 is loaded into the hole, rebar side up. Next, the exposed end of the rebar is struck with a hammer, and preferably a three-pound hammer, until the shell section 14 bottoms out at the bottom of the drilled hole, as shown in FIGS. 3 and 4. As those with skill in the art will appreciate, as the rebar is hammered, the wedge 16 is driven into the hollow inner core of the shell section 16 and, due to the shape of the wedge, the grippers 18 are driven outward so as to contact the cement or masonry and provide a retaining force. It has been found that in order to ensure that the anchor is completely set, the rebar, in one embodiment of the invention, must be driven downward at least ⅜ of an inch. After an installer has some installation experience, he or she will be able to determine a proper anchor setting by the solid ring sound that is produced when the shell portion 14 bottoms out in the hole.

It should be noted that while in one embodiment of the invention, the wedge 16 is not integral with the rebar 12, it is possible for the wedge and rebar to form an integral piece. Indeed, as shown in FIG. 9, the rebar 12 and the wedge 16 are integral. In such an embodiment, the shell 14 would preferably be slidably attached to the rebar 12, and during installation, an installer will, after drilling the appropriately-sized hole, place the wedge portion 16 of the rebar 12 at the bottom of the hole and drive the shell portion 14 toward the wedge portion 16 in the direction of the arrow shown in FIG. 9, using an appropriate tool, for instance a hollow cylindrical pipe 32 that sides over the rebar and contacts the end portion 34 of the shell portion 14. As can be appreciated, once the shell 14 is driven into wedge portion 16, the shell will expand to lock the rebar 12 in place in the hole. Also, it is envisioned that the frictional forces and some deformation of the shell 14 will lock the shell 14 to the rebar 12 upon the shell being fully driven into the wedge portion 16. It is also envisioned that a preferred method of installation will involve the pipe tool 32 being of such a length that after the pipe tool 32 has driven the shell portion 14 down a desired distance, the top of the pipe tool 32 will be flush with the exposed portion of rebar 12, thus providing an installer with a visual indication that the anchoring system has been properly installed.

The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The description was selected to best explain the principles of the invention and their practical application to enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention not be limited by the specification, but be defined by the claims set forth below. 

1. An anchoring device comprising: a length of reinforcing material; a shell section attached to said reinforcing material, wherein said shell section has a hollow inner core and is segmented on one end thereof; a wedge located at least partially in the inner core of said shell section.
 2. The anchoring device of claim 1, wherein said reinforcing material is rebar.
 3. The anchoring device of claim 1, wherein said reinforcing material is threaded rod;
 4. The anchoring device of claim 1, wherein said shell section has four segments.
 5. The anchoring device of claim 1, wherein said shell section contains barbs on an outside portion thereof.
 6. The anchoring device of claim 5, wherein said barbs are circumferential.
 7. The anchoring device of claim 1, wherein said wedge us frusto-conical in shape.
 8. The anchoring device of claim 1, wherein said wedge contains barbs on an outside portion thereof.
 9. The anchoring device of claim 8, wherein said barbs are circumferential.
 10. The anchoring device of claim 8, wherein said inner core of said shell section contains locking detents, wherein said locking detents are designed to engage said barbs on said wedge to prevent said wedge from being removed from said inner core.
 11. The anchoring device of claim 1, wherein said shell portion is attached to said reinforcing structure by a crimp connection.
 12. A method of attaching a reinforcing structure having a first end, a second end, and a longitudinal axis to an existing substrate, said method comprising: drilling an aperture in said substrate; inserting said first end of said reinforcing structure in said aperture, said first end containing a shell portion attached thereto, said shell portion having a hollow inner core and being segmented on one end thereof, said shell portion further containing a wedge partially inserted in said hollow inner core; hammering said second end of said substrate in a direction parallel to said longitudinal axis and toward said aperture, wherein said hammering causes said wedge to be driven into said hollow inner core, thereby causing the segmented end of said shell portion to flare outward and against the walls of said aperture.
 13. The method of claim 12, wherein said reinforcing structure is rebar.
 14. The method of claim 12, wherein said reinforcing structure is threaded rod.
 15. The method of claim 12, wherein said shell portion has four segments on said one end thereof.
 16. The method of claim 12, wherein said shell portion has circumferential barbs on an outer portion thereof.
 17. The method of claim 12, wherein said wedge has circumferential barbs on an outer portion thereof.
 18. An anchoring device comprising: a length of reinforcing material; a shell section attached to said reinforcing material, wherein said shell section has a hollow inner core; and a wedge proximate one end of said reinforcing material.
 19. The anchoring device of claim 18, wherein said shell section is segmented and wherein said shell section is slidably attached to said reinforcing material.
 20. The anchoring device of claim 18, wherein said wedge is integral with said reinforcing material 